scholarly journals Raman study of electron-phonon coupling in thin films of the spinel oxide superconductor LiTi2O4

2017 ◽  
Vol 96 (9) ◽  
Author(s):  
D. Chen ◽  
Y.-L. Jia ◽  
T.-T. Zhang ◽  
Z. Fang ◽  
K. Jin ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxide Superconductor ◽  
Phonon Coupling ◽  
Spinel Oxide ◽  
Electron Phonon Coupling ◽  
Raman Study

scholarly journals Anisotropic electron-phonon coupling in the spinel oxide superconductor LiTi2O4

2017 ◽  
Vol 95 (5) ◽  
Author(s):  
Ge He ◽  
Yanli Jia ◽  
Xingyuan Hou ◽  
Zhongxu Wei ◽  
Haidong Xie ◽  
...  
Keyword(s):  
Oxide Superconductor ◽  
Phonon Coupling ◽  
Spinel Oxide ◽  
Electron Phonon Coupling

scholarly journals Creating better superconductors by periodic nanopatterning

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Milan Allan ◽  
Mark H Fischer ◽  
Oliver Ostojic ◽  
Arjo Andringa
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Numerical Methods ◽  
Model Calculation ◽  
Lattice Mismatch ◽  
Specific Pattern ◽  
Design Parameters ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Correct Design

The quest to create superconductors with higher transition temperatures is as old as superconductivity itself. One strategy, popular after the realization that (conventional) superconductivity is mediated by phonons, is to chemically combine different elements within the crystalline unit cell to maximize the electron-phonon coupling. This led to the discovery of NbTi and Nb_33Sn, to name just the most technologically relevant examples. Here, we propose a radically different approach to transform a ‘pristine’ material into a better (meta-) superconductor by making use of modern fabrication techniques: designing and engineering the electronic properties of thin films via periodic patterning on the nanoscale. We present a model calculation to explore the key effects of different supercells that could be fabricated using nanofabrication or deliberate lattice mismatch, and demonstrate that specific pattern will enhance the coupling and the transition temperature. We also discuss how numerical methods could predict the correct design parameters to improve superconductivity in materials including Al, NbTi, and MgB_22.

Influence of disorder strength on the superconducting mechanism of MgB2

2021 ◽  
Author(s):  
Jung Min Lee ◽  
Soon-Gil Jung ◽  
Younseok Han ◽  
Tae-Ho Park ◽  
Jae Kyung Jang ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Electronic System ◽  
Coupling Constants ◽  
Disorder Strength ◽  
Coupling Constant ◽  
Phonon Coupling ◽  
Normal State Resistivity ◽  
Electron Phonon Coupling ◽  
Effect Of Disorder

Abstract We investigate the effect of disorder on the superconducting mechanism of MgB2 thin films using low-energy ion irradiation. The c-axis lattice constant and T c of MgB2 thin films change systematically as the magnitude of disorder, which corresponds to the value of average displacements per atom (dpaavg ), increases. Here, dpaavg is controlled by the amount of irradiated ions. The dpaavg dependence of the electron-phonon coupling constants (λ) is estimated using the McMillan equation. For dpaavg ≤ 0.049, λ is linearly proportional to dpaavg . On the other hand, for dpaavg > 0.049, the T c of the disordered MgB2 deviates from the linear fitting curve, and insulating behavior is observed in the normal state resistivity. These results indicate that the superconducting mechanism of MgB2 can be changed by the electronic system caused by disorder strength affecting the electron-phonon coupling constant λ.

scholarly journals Probing the electron-phonon coupling in MgB 2 through magnetoresistance measurements in neutron irradiated thin films

2008 ◽  
Vol 81 (6) ◽  
pp. 67006 ◽  
Author(s):  
M. Monni ◽  
I. Pallecchi ◽  
C. Ferdeghini ◽  
V. Ferrando ◽  
A. Floris ◽  
...  
Keyword(s):  
Thin Films ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

Anomalous low-temperature Raman scattering in a–Si1−xHx

1995 ◽  
Vol 10 (6) ◽  
pp. 1362-1370 ◽  
Author(s):  
D.M. Bhusari ◽  
Alka Kumbhar ◽  
S.T. Kshirsagar
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Raman Scattering ◽  
Cross Section ◽  
Hydrogenated Amorphous Silicon ◽  
Phonon Coupling ◽  
Scattered Intensity ◽  
Electron Phonon Coupling ◽  
Scattering Measurements ◽  
Hydrogenated Amorphous

We have reported here on low-temperature Raman scattering measurements on thin films of hydrogenated amorphous silicon (α-Si:H) alloys having different H contents. The Stoke's intensity, 77KITO, scattered at 77 K by the TO-phonon is found to be several times greater than its corresponding magnitude (300KITO) at 300 K. The ratio (77KITO/300KITO) is observed to vary exponentially with an increase in H concentration of the film. After eliminating various possible contributions to the scattering cross section, and therefore to the scattered intensity, this anomalous light scattering at 77 K is attributed to the possibility of polarizability modulation, which is believed to be caused due to a possible reduction in light-induced migration of H in α-Si:H and to the charge-carrier-induced enhancement of electron phonon coupling at 77 K.

Large electronic sputtering yield of nanodimensional Au thin films: Dominant role of thermal conductivity and electron phonon coupling factor

2017 ◽  
Vol 121 (9) ◽  
pp. 095308 ◽  
Author(s):  
Udai B. Singh ◽  
Compesh Pannu ◽  
Dinesh C. Agarwal ◽  
Sunil Ojha ◽  
Saif A. Khan ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Dominant Role ◽  
Coupling Factor ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Sputtering Yield ◽  
Au Thin Films

Raman Scattering and Superconductivity of Alkali-Fullerene Materials

1992 ◽  
Vol 270 ◽  
Author(s):  
J. S. Lannin ◽  
M. G. Mitch ◽  
W. Bacsa ◽  
S. J. Chase
Keyword(s):  
Thin Films ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Solid Solutions ◽  
Thick Films ◽  
Ultrathin Film ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Scattering Measurements ◽  
Different Thickness

ABSTRACTRaman scattering measurements in alkali—fullerene alloys in ultrathin and thin films provide evidence for variations in electron—phonon coupling. For x — 3similar behavior of Rb3 C60 films of different thickness support substantial electron—phonon induced damping of specific Hg(i) modes derived from intramolecular modes of C60. In 400A thick films a reduction of induced scattering from Raman inactive C60 modes substantiates the importance ofHg(2), but not Hg(3) modes for phonon—mediated superconductivity. In contrast to RbxC60 and KxC60 ultrathin film solid solutions, similar Raman spectra for NaxC60 indicate substantially reduced coupling consistent with the absence of superconductivity in this system.

scholarly journals New Insights into the Role of Weak Electron–Phonon Coupling in Nanostructured ZnO Thin Films

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 632 ◽  
Author(s):  
Ashish Gandhi ◽  
Wei-Shan Yeoh ◽  
Ming-An Wu ◽  
Ching-Hao Liao ◽  
Dai-Yao Chiu ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Scattering ◽  
High Performance ◽  
Zno Thin Films ◽  
Phonon Coupling ◽  
X Ray Diffraction ◽  
Electron Phonon Coupling ◽  
Weak Electron ◽  
Confined System

High-quality crystalline nanostructured ZnO thin films were grown on sapphire substrates by reactive sputtering. As-grown and post-annealed films (in air) with various grain sizes (2 to 29 nm) were investigated by scanning electron microscopy, X-ray diffraction, and Raman scattering. The electron–phonon coupling (EPC) strength, deduced from the ratio of the second- to the first-order Raman scattering intensity, diminished by reducing the ZnO grain size, which mainly relates to the Fröhlich interactions. Our finding suggests that in the spatially quantum-confined system the low polar nature leads to weak EPC. The outcome of this study is important for the development of nanoscale high-performance optoelectronic devices.

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